Although this invention is applicable to the ultrasonic inspection of various types of composite products, it has been found to be particularly useful in the environment of ultrasonic inspection of the curved components or panels or airplane engine nacelles. Therefore, without admitting the applicability of the invention to "curved components of airplane engine nacelles", the invention will be described in such environment.
It is well known to use ultrasonic inspection to determine the existence and location of any structure defects in curved composite components and/or products and to display the results on the screen of a cathode ray tube. Heretofore, it has been necessary to have a full compound contoured scanning system or to scan the composite component in predetermined zones using inspection equipment designed for planar inspection applications. These two methods require either expensive and complicated equipment or long periods of time to run the testing, which results in either a large capital investment or an expensive test period. In the past, many stiffened nacelle panels required multiple scans to perform an inspection of a nacelle panel. The web area of the stiffened nacelle panel can be inspected with the ultrasonic transducers oriented at generally ninety degrees to the web area while the stiffened areas must be run with the ultrasonic transducers oriented at an angle other than normal with respect to the web area.
The present invention provides apparatus which moves the nacelle panel through an ultrasonic inspection zone while maintaining control of the panel to always provide a nearly horizontal orientation of the surface of the nacelle panel at the inspection zone as the panel is moved through the ultrasonic inspection zone. The panel is scanned ninety degrees to the direction in which the panel is moved through the ultrasonic inspection zone. The test time using the apparatus of the present invention is approximately one-tenth the time needed when using the prior art rectilinear apparatus.